package com.zenithmind.document.service.impl;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.zenithmind.document.pojo.dto.DocumentCreateDTO;
import com.zenithmind.document.pojo.dto.DocumentUpdateDTO;
import com.zenithmind.document.pojo.dto.DocumentUploadDTO;
import com.zenithmind.document.pojo.domain.Document;
import com.zenithmind.document.pojo.query.DocumentQueryDTO;
import com.zenithmind.document.pojo.vo.DocumentDetailVO;
import com.zenithmind.document.pojo.vo.DocumentStatisticsVO;
import com.zenithmind.document.pojo.vo.DocumentVO;
import com.zenithmind.document.service.*;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * 文档门面服务实现类
 * 遵循门面模式：为复杂的子系统提供简化的接口
 * 遵循单一职责原则：专注于协调各个专门的服务
 * 遵循依赖倒置原则：依赖抽象接口而不是具体实现
 * 
 * @author ZenithMind Team
 * @since 2025-01-09
 */
@Slf4j
@Service("documentFacadeService")
@RequiredArgsConstructor
public class DocumentFacadeServiceImpl implements DocumentFacadeService {

    private final DocumentBasicService documentBasicService;
    private final DocumentSearchService documentSearchService;
    private final DocumentProcessService documentProcessService;
    private final DocumentStatisticsService documentStatisticsService;
    private final DocumentService documentService;

    // ========== 基础文档操作委托 ==========
    
    @Override
    public DocumentVO uploadDocument(DocumentUploadDTO uploadDTO) {
        log.info("门面服务：上传文档 - {}", uploadDTO.getFile().getOriginalFilename());
        return documentBasicService.uploadDocument(uploadDTO);
    }
    
    @Override
    public DocumentVO createDocument(DocumentCreateDTO createDTO) {
        log.info("门面服务：创建文档 - {}", createDTO.getName());
        return documentBasicService.createDocument(createDTO);
    }
    
    @Override
    public Boolean updateDocument(String id, DocumentUpdateDTO updateDTO) {
        log.info("门面服务：更新文档 - {}", id);
        return documentBasicService.updateDocument(id, updateDTO);
    }
    
    @Override
    public Boolean deleteDocument(String id) {
        log.info("门面服务：删除文档 - {}", id);
        return documentBasicService.deleteDocument(id);
    }
    
    @Override
    public DocumentDetailVO getDocumentDetail(String id, String userId) {
        log.info("门面服务：获取文档详情 - id={}, userId={}", id, userId);
        
        // 先记录访问
        recordDocumentAccess(id, userId, "view");
        
        return documentBasicService.getDocumentDetail(id, userId);
    }
    
    @Override
    public IPage<DocumentVO> getDocumentPage(DocumentQueryDTO queryDTO) {
        log.info("门面服务：分页查询文档");
        return documentBasicService.getDocumentPage(queryDTO);
    }
    
    // ========== 文档搜索委托 ==========
    
    @Override
    public List<DocumentVO> searchDocuments(String keyword, String userId, Integer limit) {
        log.info("门面服务：搜索文档 - keyword={}, userId={}, limit={}", keyword, userId, limit);
        return documentSearchService.searchDocuments(keyword, userId, limit);
    }
    
    @Override
    public List<DocumentVO> getHotDocuments(Integer limit) {
        log.info("门面服务：获取热门文档 - limit={}", limit);
        return documentSearchService.getHotDocuments(limit);
    }
    
    // ========== 文档处理委托 ==========
    
    @Override
    public String convertDocument(String id, String targetFormat, String userId) {
        log.info("门面服务：转换文档格式 - id={}, targetFormat={}, userId={}", id, targetFormat, userId);
        
        // 检查权限
        if (!checkDocumentPermission(id, userId, "convert")) {
            throw new RuntimeException("无权限转换此文档");
        }
        
        return documentProcessService.convertDocument(id, targetFormat, userId);
    }
    
    @Override
    public byte[] downloadDocument(String id, String userId) {
        log.info("门面服务：下载文档 - id={}, userId={}", id, userId);
        
        // 检查权限
        if (!checkDocumentPermission(id, userId, "download")) {
            throw new RuntimeException("无权限下载此文档");
        }
        
        // 记录下载
        recordDocumentAccess(id, userId, "download");
        
        // 实现文件下载逻辑
        try {
            // 获取文档信息
            Document document = documentService.getById(id);
            if (document == null) {
                throw new RuntimeException("文档不存在");
            }

            // 获取文件路径
            String filePath = document.getFilePath();
            if (filePath == null || filePath.trim().isEmpty()) {
                throw new RuntimeException("文件路径不存在");
            }

            // 从文件存储系统读取文件
            return readFileFromStorage(filePath);

        } catch (Exception e) {
            log.error("文件下载失败: id={}, userId={}", id, userId, e);
            throw new RuntimeException("文件下载失败: " + e.getMessage());
        }
    }
    
    @Override
    public String previewDocument(String id, String userId) {
        log.info("门面服务：预览文档 - id={}, userId={}", id, userId);
        
        // 检查权限
        if (!checkDocumentPermission(id, userId, "view")) {
            throw new RuntimeException("无权限预览此文档");
        }
        
        // 记录访问
        recordDocumentAccess(id, userId, "preview");
        
        return documentProcessService.generateDocumentPreview(id);
    }
    
    // ========== 文档统计委托 ==========
    
    @Override
    public DocumentStatisticsVO getDocumentStatistics(String documentId) {
        log.info("门面服务：获取文档统计 - documentId={}", documentId);
        return documentStatisticsService.getDocumentStatistics(documentId);
    }
    
    @Override
    public Boolean recordDocumentAccess(String documentId, String userId, String accessType) {
        log.info("门面服务：记录文档访问 - documentId={}, userId={}, accessType={}", documentId, userId, accessType);
        return documentStatisticsService.recordDocumentAccess(documentId, userId, accessType);
    }
    
    // ========== 权限管理 ==========
    
    @Override
    public Boolean checkDocumentPermission(String documentId, String userId, String permission) {
        log.info("门面服务：检查文档权限 - documentId={}, userId={}, permission={}", documentId, userId, permission);
        return documentBasicService.checkDocumentPermission(documentId, userId, permission);
    }
    
    @Override
    public Boolean validateDocumentOwnership(String documentId, String userId) {
        log.info("门面服务：验证文档所有权 - documentId={}, userId={}", documentId, userId);
        return documentBasicService.validateDocumentOwnership(documentId, userId);
    }

    // ========== 私有辅助方法 ==========

    /**
     * 从存储系统读取文件
     */
    private byte[] readFileFromStorage(String filePath) {
        try {
            // TODO: 实现真实的文件存储读取逻辑
            // 这里应该根据存储类型（本地文件系统、云存储等）选择不同的读取方式

            if (filePath == null || filePath.trim().isEmpty()) {
                throw new RuntimeException("文件路径为空");
            }

            // 模拟文件读取
            log.info("从存储系统读取文件: filePath={}", filePath);

            // 这里应该实现真实的文件读取逻辑：
            // 1. 本地文件系统：Files.readAllBytes(Paths.get(filePath))
            // 2. 云存储：调用云存储SDK
            // 3. 分布式文件系统：调用相应API

            // 临时返回空数组，避免空指针异常
            return new byte[0];

        } catch (Exception e) {
            log.error("从存储系统读取文件失败: filePath={}", filePath, e);
            throw new RuntimeException("文件读取失败: " + e.getMessage());
        }
    }
}
